Such an operating liquid tank is known, for example, from DE 10 2010 011 151 A1 as a tank for holding a reducing agent. The reducing agent may be, in particular, a urea solution. For the tank according to the present application a reducing agent, in particular an aqueous urea solution, is preferably also conceivable as the operating liquid, but the operating liquids that can be held in the tank should not be limited to such reducing agents.
A problem of the generic tank is the conveying of operating liquid out of the tank, in order to deliver the liquid to a place of use.
Several solutions for this are known in the prior art. For example, a conveying device together with its drive can be installed in a separate module, which module is then inserted into an opening in the tank wall and closes said opening. Firstly, this leads to a joining point in the region of the module arrangement and also leads to necessary seals on the module, in order to prevent operating liquid from reaching components of the pump assembly that are sensitive therefor. In this case especially the usual electrical pump drive should be kept away from the fluid.
According to another known solution, the pump drive is arranged outside the tank wall and the pump is arranged inside the tank wall, wherein a drive shaft of the pump drive then passes through the tank wall in order to transmit kinetic energy to the pump in order to drive it. This passage point should then be sealed particularly against leakage of liquid from the tank.
A further possibility consists of arranging the entire pump assembly outside the tank and connecting it to the interior of the tank by conduits that pass through the tank wall. Of all the three possibilities, this one leads to the greatest possible requirement for space, so that with a predetermined installation space for the operating liquid tank the storage volume that is actually usable is smallest in the last-mentioned solution.